Modular articulating cement spacer

ABSTRACT

The present teachings provide a modular articulating cement spacer mold for forming a temporary implant comprising a mold first portion, a mold second portion, and a ventilation forming surface feature on an interior surface of at least one of the mold first portion or the mold second portion. The first mold portion and the second mold portion have corresponding interior surfaces that form a cavity therebetween.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.12/390,084 filed Feb. 20, 2009, which is a continuation-in-part of U.S.patent application Ser. No. 11/955,601 filed on Dec. 13, 2007, now U.S.Pat. No. 7,637,729 issued on Dec. 29, 2009. The entire disclosures ofthe above applications are incorporated herein by reference.

FIELD

The present disclosure relates to a spacer mold, and more particularly,to a modular articulating two-stage cement hip spacer mold.

BACKGROUND

A natural joint may undergo degenerative changes due to a variety ofetiologies. When these degenerative changes become so far advanced andirreversible, it may ultimately become necessary to replace the naturaljoint with a joint prosthesis. However, due to any number of reasons, asmall portion of patients that undergo such orthopedic surgicalprocedures may suffer from infections at the surgical site and generallyaround the implanted joint prosthesis. In order to cure such aninfection in a two-stage re-implantation, the implanted joint prosthesismay be removed, the site is thoroughly debrided and washed, antibioticsare applied to the infected site via a temporary implant until theinfection is eliminated, and a new revision type joint prosthesis isthen implanted during a subsequent orthopedic surgical procedure.

Accordingly, there is a need for apparatus and methods to facilitatetwo-stage re-implantation which expedite healing at the site, provide abetter fitting implant, reduce the amount of time a patient isbedridden, increase the efficiency of the surgical procedure whilereducing the surgical time and cost, eliminate any re-cleaning orre-sterilizing steps, and create a customizable procedure.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features.

In various embodiments a modular articulating cement spacer mold forforming a temporary implant is provided. The modular articulating cementspacer mold comprises a first mold, a second mold, and a connectinghinge. In various embodiments, the modular articulating cement spacermold can include a self-cleaning mechanism, a self-securing device, or aventilation forming feature.

Further areas of applicability will become apparent from the descriptionprovided herein. The description and specific examples in this summaryare intended for purposes of illustration only and are not intended tolimit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1 depicts an exploded view of a head mold component and variousconnection features according to various embodiments;

FIG. 2A depicts a interior view of a first portion of the head moldcomponent according to various embodiments;

FIG. 2B depicts an exterior view of a first portion of the head moldcomponent according to various embodiments;

FIG. 3A depicts an interior view of a second portion of the head moldcomponent according to various embodiments;

FIG. 3B depicts an exterior view of a second portion of the head moldcomponent according to various embodiments;

FIGS. 4A-4C depict various views of a self-cleaning cap according tovarious embodiments;

FIGS. 5A-5B depict various views of a head connector portion accordingto various embodiments;

FIG. 6 depicts an exploded view of a stem mold component and variousconnection features according to various embodiments;

FIG. 7 depicts an exploded view of a stem mold component according tovarious embodiments;

FIG. 8 depicts a perspective view of a femoral stem insert according tovarious embodiment;

FIGS. 9A-9B depict a temporary femoral head implant according to variousembodiments;

FIG. 10 depicts a temporary femoral stem implant according to variousembodiments;

FIGS. 11A-11B depict a self-separating mechanism according to variousembodiments; and

FIGS. 12A-12B depict a self-separating mechanism according to variousembodiments.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference tothe accompanying drawings.

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses. Althoughcertain examples and surgical methods disclosed herein are inconjunction with a temporary hip implant, it is understood that themolds and surgical methods disclosed herein can be used in anyorthopedic revision surgery for any area in the patient.

Although the terms first, second, third, etc. may be used herein todescribe various elements, components, regions, layers and/or sections,these elements, components, regions, layers and/or sections should notbe limited by these terms. These terms may be only used to distinguishone element, component, region, layer or section from another region,layer or section. Terms such as “first,” “second,” and other numericalterms when used herein do not imply a sequence or order unless clearlyindicated by the context. Thus, a first element, component, region,layer or section discussed below could be termed a second element,component, region, layer or section without departing from the teachingsof the example embodiments.

Spatially relative terms, such as “inner,” “outer,” “beneath”, “below”,“lower”, “above”, “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. Spatiallyrelative terms may be intended to encompass different orientations ofthe device in use or operation in addition to the orientation depictedin the figures. For example, if the device in the figures is turnedover, elements described as “below” or “beneath” other elements orfeatures would then be oriented “above” the other elements or features.Thus, the example term “below” can encompass both an orientation ofabove and below. The device may be otherwise oriented (rotated 90degrees or at other orientations) and the spatially relative descriptorsused herein interpreted accordingly.

Referring to FIGS. 1 and 6, the present teachings provide a modulararticulating cement spacer mold for forming a temporary implant. Thesystem includes a head component mold 100, as shown in FIG. 1, and astem component mold 200, as shown in FIG. 6. It is understood thatvarious features from the head component mold 100 and the stem componentmold 200 can be interchanged within the scope of the present teachings.The modularity of the present teachings allows the surgeon to create ahighly customized implant based on both the head and the stem size needsof the patient. This is beneficial in revision surgery where thecondition of either the acetabulum or the femur may differ to the extentthat a monolithic temporary implant may not best meet the needs of thepatient. The present temporary implants are optimized for strength andreinforce the high stress areas along the neck of the implant. It isunderstood that the present teachings, while illustrative of a hipimplant, can also be used for other orthopedic uses, including, forexample, a shoulder or a knee.

The molds 100 and 200 can be formed from any biocompatible materialincluding various polymers. In various embodiments, the polymericmaterial can be sufficiently rigid to provide structure to the resultantimplant components 300 and 400 as shown in FIGS. 9A-10. In variousembodiments, the molds 100 and 200 are formed from a plastic, such aspolyethylene, polypropylene, or polyetheretherketone (PEEK) includingcarbon reinforced PEEK. Such materials have a sufficiently highstiffness such that the molds 100 and 200 will not sag or beunintentionally deformed upon handling. It is understood that othermaterials can also be used to form the molds 100 and 200, includingsilicone, for example, Dow Q7-4780 or any other 80 durometer silicone orincluding rubber. It should be noted that the material selected shouldgenerally not adversely react with the bone cement and antibioticselected. In various embodiments, the materials used may be transparentor partially transparent to allow an operator to observe the formationof the temporary implant. The head component mold portions 102 and 104or the stem component mold portions 202 and 204 can be formed by variousconventional molding techniques such as injection molding, compressionmolding, blow molding, spin casting, etc.

Turning to FIG. 1, the head component mold 100 can be used to form thetemporary implant head component 300 as shown in FIGS. 9A and 9B.Returning to FIG. 1, the head component mold 100 includes a first headcomponent mold portion 102 and a second component mold portion 104. Thefirst head component mold portion 102 and the second component moldportion 104 each generally forms a portion of a “clamshell” and definecavity portions 106 a and 106 b, respectively, such that upon connectingand closing the portions 102 and 104. The area between the cavityportions 106 a and 106 b accommodates the cement, a head connector 110,and a head connector alignment member 112. It is understood that whilethe head component mold 100 is depicted as connecting along a sagittalplane and the stem component mold 200 is depicted as connecting alongthe coronal plane, as shown in FIG. 6, the placements are not limitingand are merely exemplary. Modifications to the planar alignment (i.e.:either sagittal alignment or both coronal alignment, for example) arewithin the scope of the present teachings. Further, the presentdisclosure is not limited to embodiments where there are only a firstmold portion and a second mold portion. It is understood that anyplurality of components can be used to form the mold portion.

Referring to FIGS. 1 and 2A-2B, the head component first mold portion102 includes an outer surface 120, an inner surface 122, and connectioncomponents 124 a which further defines a series of openings 126 atherein to accommodate a connection component pin 128 (only shown inFIG. 1). It should be noted that the hinge pin 128 can be molded intothe openings 126 a. Also, as will be illustrated below, it is understoodthat the hinge pin 128 can also be formed into separate pieces. Minormodifications of the hinge are within the scope of the presentteachings. The perimeter or edge 130 of the head component first moldportion 102 surrounds a raised dome region 132 which extends upwardlyfrom the outer surface 120. The raised region 132 provides thesemi-hemispherical shape to the resultant implant as shown in FIG. 9A.

Returning to FIGS. 1 and 2A-2B, on the end of the edge 130 which isopposite to the end having the connection component 124 b, the headcomponent first mold portion 102 defines an opening 134 a to accommodatea screw 136 to secure the head component first mold portion 102 with thehead component second mold portion 104. As best shown in FIGS. 11A and11B, the opening 134 a includes a ledge 135 which is deformable and canbe bent over a region of the screw 136 to form a fold-over region 137(FIGS. 11A and 11B) to rotatably capture the screw 136 and provide aself-securing device or a dual securing and separating mechanism tocombine the first mold portion 102 and second mold portion 104 or toseparate them. In various embodiments, the fold over region 137 may be aseparately molded piece that is secured to the opening 134 a. Forexample, the fold over region 137 may be sonically welded to the opening134 a.

In an exemplary use, advancing the screw 136 into the opening 134 a andsecuring with the threads 134 b secures the first mold portion 102 andsecond mold portion 104 together. This securement can be furthersupported by forming a fold-over region 137 over a portion of the screw136. By fixing the ledge 135 over the screw 136 to form a fold-overregion 137, the operator is provided a bearing surface against which thescrew 136 cannot advance. When the operator rotates the screw 136 as toback it out from the threaded opening 134 b, the ledge 135 and fold-overregion 137 trap the screw 136, prevent the backward rotation of thescrew 136 from removing the screw 136, and instead help pry apart thefirst mold portion 102 and second mold portion 104.

With reference to FIGS. 3A and 3B, the head component second moldportion 104 includes an inner surface 150, an outer surface 152, and aconnection component 124 b defining hook-shaped passages 126 b therein.The perimeter of the head component second mold portion 104 forms anedge 154 which surrounds a recessed region 156 which extends downwardlyfrom the outer surface 152 and forms the cavity portion 106 b. The outersurface 152 is flat relative to the raised region 132 of the firstportion 102 as shown in FIG. 1 to provide the appropriate shape for thelower region of the femoral head 300 as depicted in FIG. 9B. Returningto FIGS. 3A and 3B, the recessed region 156 includes a cylindricalinterior raised ring or lip 158 in which the head connector 110cylindrical region 119 may be retained by an o-ring (not shown) andfurther secured by the abutment member 117 as best shown in FIG. 1.

Returning to FIGS. 3A and 3B, the outer surface 152 of the headcomponent second mold portion 104 further includes a threaded opening160 or filling port which functions in multiple capacities as will bedetailed later herein. The head component second mold portion defines aninternally threaded opening 134 b.

The head component second mold portion 104 and the recessed portion 156provide surface features 162 which, upon filling the head component mold100, provide depressions 302 in the articulating head 300 of the finalimplant, as shown in FIG. 9B, which are the negative impression of thesurface features 162. While surface features which form positiveimpressions can be used on the implant, those forming negativeimpressions facilitate easy removal of the temporary implant bypreventing a potentially positive impression from becoming lodged into atissue. The resultant depressions 302 increase the surface area of theresultant articulating head 300. Suitable depressions 302 include, butare not limited to grooves, dimples, hemispheres, cones, stars, ridges,notches, and the like. The depressions 302 can also include individualletters or combinations of letters and designs, such as a logo or partnumber.

It is understood that in such embodiments, the surface features 162 canbe included on either of the head component first mold portion 102 orthe head component second mold portion 104. The surface area of thetemporary implant 300 can be increased by from about 1% up to 50% ormore depending on the combination of surface area increasing features162 employed in the mold 100. An exemplary, but non-limiting, benefit ofthe increased surface area is the increased amount of antibiotic orother therapeutic material (i.e.: drugs, vitamins, etc.) from thesurface of the temporary implant to the defect site. The increaseddelivery of the antibiotic or other therapeutic material expediteshealing and minimizes the recovery time of the patient.

Referring to FIGS. 1 and 5A-5B, the head connector 110 can define ahollow chamber (shown in phantom) formed by a metal insert containedwithin the head component mold 100. The head connector 110 exteriorsurface defines flats 111 to assist in the fit of the head connector110. In addition, the flats 111 prevent the rotation of the headconnector 110 in the cement. The head connector interior surface definesa shoulder 113 which mimics the outer contour of the head connector. Theshoulder 113 sits atop the head connector alignment member 112 as willbe detailed later herein. Exemplary metals for the head connector 110include stainless steel, titanium, cobalt, and the like and variousalloys thereof. The head connector 110 can mate with the femoral stemcomponent using a taper fit, such as a Morse taper, as a non-limitingexample. The head connector 110 can optionally include surfaceroughening features or a surface texture to facilitate placement and fitwith the stem implant 400.

In various embodiments, the head connector 110 is a female connector andis contained within the head component mold 100 such that upon fillingthe head component mold 100 with a material, such as a bone cement, avoid volume will be defined in the articulating head portion of thetemporary implant having a volume that is roughly equivalent to the voidvolume defined by the head connector 110. In still other embodiments,the head connector 110 can be a male connector and is contained at aregion of the head component mold 100 and does not define a hollowregion within the head component mold 100 upon filling the head moldwith the material.

In either embodiment, the head connector 110 is fixed in the headcomponent mold 100 so that it is not inadvertently displaced. Thefixation of the head connector 110 is facilitated by the head connectoralignment member 112. Further the head connector alignment member 112can be made of a material which facilitates easy removal of the headconnector alignment member 112 from the head connector 110. In variousembodiments, the head connector alignment member 112 can be formed of apolymer material, such as polyethylene or PEEK. The head connectoralignment member 112 can be formed of the same material as the headcomponent mold 100 or it can be made of a different material.

The head connector alignment member 112 includes a tapered region 115,an abutment member 117, and a cylindrical region 119. As depicted, thehead connector alignment member 112 can be hollow. The tapered region115 mates with the interior region 166 of the head connector 110. Theabutment member 117 is sized to extend beyond the perimeter of theopening 158 to prevent the tapered region 115 from passing therethrough.The head connector alignment member 112 is retained in the headcomponent second mold portion 104 by a lip 158 or ring about theinterior region 156 of the head component second mold portion 104. Thelip 158 and the head connector alignment member 112 can be maintained incontact using friction between the materials. Any other suitableretention technique can also be employed in accords with the presentteachings.

Inclusion of the head connector alignment member 112 in the headcomponent mold 100 helps maintain a material-tight integrity of the headcomponent mold 100 and prevents leakage of a filling material therefrom.Further, in various embodiments, the hollow alignment member 112facilitates access to the head connector 110 and allows a user to pressagainst the head connector 110 to free the implant from the mold 104. Invarious embodiments, the head component mold 100 and the head connectoralignment member 112 can be provided as a single unit. The headconnector alignment member 112 is used for temporary securing purposesonly and is not included in the final articulating head implant 300.

To connect the head component mold first portion 102 with the headcomponent second mold portion 104, the offset connection components 124a and 124 b are interlaced to form a piano hinge which is connected overthe pin or rod 128. The pin 128 is placed through the openings 126 aformed in the connection component 124 a of the head component moldfirst portion 102. This can be achieved by providing a pin 128 which haspreviously been insert molded into the openings 124 a. Next, the pin 128is hooked underneath the hook shaped passages 126 b to removably connectthe head component mold first portion 102 with the head component secondmold portion 104. In addition, the removal of the pin 128 allows head300 to be removed from portion 104.

Further, with reference to FIG. 1, the head component mold first portion102 and second portion 104 can be secured together by disposing a screw136 through the openings 134 a and 134 b, which are concentric and alignwhen the head component mold first portion 102 and head component moldsecond portion 104 are interlaced at the connection components 124 a and124 b. It is understood that although a single pair of openings 134 aand 134 b are provided, the head component mold 100 could includemultiple pairs of matching openings placed around the perimeter 130 andperimeter 154 of the head component mold 100. As detailed later herein,the opening 134 a is manipulated to provide a mechanical advantage toseparate the implant from the head component mold first portion 102 andhead component mold second portion 104.

The threaded opening 160 in the head component second mold portion 104provides an access through which to deliver a material to fill the headcomponent mold 12. It is understood that the threaded opening 160 can bedefined at any region of the head component mold 100 and is not limitedto placement on the second mold portion 104. The threaded opening 160can be sized to accommodate a nozzle of a delivery device or a syringethrough which a material is delivered to the head component mold 100.

Turning to FIGS. 4A-4C, a self-cleaning cap 168 is provided. Theself-cleaning cap 168 helps to provide a flush region on the implant 300or 400 by removing, blocking, or segregating excess material to escapefrom the respective mold 100 or 200. Further, the self-cleaning cap canrelieve the excess material or cement which may be delivered using highpressure delivery devices. The self-cleaning cap 168 includes a head 170which defines a containment region 172. The self-cleaning cap 168further defines a threaded region 176 which defines fluted orinterrupted hollow regions 174 and terminates in a closed bottom 180.The threaded region 176 can mate with the threaded opening 160 definedby the head component mold second portion 104, as shown in FIG. 1. Asthe self-cleaning cap 168 is advanced through the threaded opening 160,any excess material contained in the head component mold 100 passesaround the closed bottom 180, up through the interrupted hollow regions174, and into the recessed containment region 172. Accordingly, theexcess material can be easily separated from the final implant andprevents the excess material from becoming an unwanted plug or anchor toundesirably secure the temporary implant to the mold. The self-cleaningcap 168 helps to prevent over-filling the mold 100 and allows theoperator to remove any excess material. The self-cleaning cap 168provides a flush implant and cleans the threaded opening 160. As shownin FIG. 9B, the closed bottom 180 of the self-cleaning cap 168 can leavean impression 304 in the implant.

Turning to FIG. 6, the stem component mold 200 includes a stem componentfirst portion 202 and a stem component second portion 204. Similar tothe head component 100 as detailed above, each portion 202 and 204generally forms a portion of a “clamshell” and define cavity portions206 a and 206 b, respectively, such that upon connecting and closing thecomponents of the stem component mold 200, the area between the cavityportions 206 a and 206 b accommodate the cement, a stem insert 210, anda stem component alignment screw 212.

Referring to FIGS. 6 and 7, the stem component mold first portion 202includes an outer surface 220, an inner surface 222, and a connectioncomponent 224 a which further defines a series of hooks 226 a toaccommodate connection component pins 228. As stated above, theconnection component pins 228 can be molded into the connectioncomponent 224 a. It is further understood that a single connectioncomponent pin can also be used. The stem component mold first portion202 also includes a perimeter or edge 230. The proximal end of the stemcomponent mold first portion 202 defines a fixation screw 212 receivingregion portion 238 a. The perimeter 230 defines a plurality of screwreceiving openings 234 a dispersed therein.

As shown in FIG. 7, the inner surface 222 includes a plurality ofsurface features 262 a, 262 b, and 262 c which upon filling the stemcomponent mold 200, provide depressions 402 a, 402 b, and 402 c in thefemoral stem 400 of the final implant as shown in FIG. 10, which are thenegative impression of the surface area increasing features 262 a, 262b, and 262 c. It is understood that the location of the surface features262 a, 262 b, and 262 c are not limited to being only on the stemcomponent mold first portion 202.

As illustrated, the surface features 262 a are raised protrusions whichwill form dimples 402 a in the femoral stem 400 at a proximal region 410of the femoral stem implant 400, as shown in FIG. 10. The surfacefeatures 262 b shown in FIG. 6 are linear raised dashes which willprovide depressions 402 b on the distal region 412 of the femoral stemimplant 400 as shown in FIG. 10. The difference between the surfacefeatures 262 a and 262 b provides a dual grip to allow a tighter hold atthe proximal region 410 of the femoral stem 400 where the surfacefeatures 262 a are smaller and more densely placed and a looser hold atthe distal region 412 where the surface features 262 b are elongated orlarger and provided in a lesser density. The longitudinal surfacefeatures 262 b are disposed such that they align with the axis of thefemoral stem to facilitate easy removal of the temporary implant 400.The surface feature 262 c is a linear raised ridge or ledge that forms aventing area 402 c which extends the length of the mold portions 202 and204 to provide ventilation in the femoral stem 400 to allow trapped airto escape past the femoral implant 400 upon insertion into a patient andprevent a vacuum upon explanting of the implant. It is understood thatalthough the raised ridge or ledge surface feature 262 c is depicted asa continuous ridge or ledge, the ventilation feature can also beprovided if the surface feature 262 c was provided in several segmentswhich extend longitudinally along the mold portions 202 and 204.

The surface features 262 a, 262 b, and 262 c detailed here are merelyexemplary, and it is understood that any combination of surface featuresor single-type of surface features can be used within the scope of thepresent teachings, including the types of surface features detailed withrespect to the head component mold 100. Further, similar to the surfacefeatures used with the head component mold 100, the various surfacefeatures 262 a, 262 b, and 262 c of the stem component mold 200 providean increase in the surface area of the femoral implant 400 whichincludes the exemplary, but non-limiting, benefit of the increasedamount of antibiotic or other therapeutic material (i.e.: drugs,vitamins, etc.) from the surface of the temporary implant 400 to thepatient to thereby expedite healing and minimize the recovery time ofthe patient.

The stem component mold second portion 204 is generally a mirror imageof the stem component mold first portion 202 with a few additions. Thestem component mold second portion 204 includes an inner surface 254, anouter surface 256, and a connection component 224 b which furtherdefines a series of hooks 226 b to accommodate the connection componentpin 228. The perimeter of the stem component mold second portion 204forms an edge 231. A threaded opening 260 is provided on the outersurface 256 which functions in multiple capacities as will be detailedlater herein. The proximal end of the stem component mold second portion204 defines a fixation screw 212 receiving region portion 238 b. Thestem component mold second portion 204 perimeter 231 defines a pluralityof screw receiving threaded openings 234 b dispersed therein. In variousembodiments, the openings 234 b include a sonically inserted metal nut(not shown) to receive the screw 212. Similar to the head component 100,the screw receiving openings 234 a define ledges 235 which can bemanipulated to provide a fold-over 237 (FIGS. 12A and 12B) to rotatablytrap the screws 236, and the openings 234 a align with threaded openings234 b.

Turning to FIG. 8, the stem insert 210 provides a reinforcing elementfor the stem implant 400 as shown in FIG. 10. Returning to FIGS. 6 and8, the stem insert 210 includes a proximal end 280, a distal end 282, atleast one distal end spacer 283, and a ledge or flange 285. The steminsert 210 is shaped to follow the general contour of the stem componentcement mold 200 as shown in FIG. 6 and can generally extend the lengthof the stem component cement mold 200. The distal end spacers 283 setoff the stem insert 210 from the sides or walls of the cavity andmaintain proper alignment thereof.

Returning to FIG. 8, at a mid-region of the stem insert 210 there is adispersion region 292 which is a hollow region or void of the steminsert 210. The dispersion region 292 provides a passage for thematerial to flow around the stem insert 210 to completely fill thecavity up to the flange 285 defined by the stem insert 210. The steminsert 210 can be made of any suitable material including polymers andmetal. In embodiments where the stem insert 210 is made from a metal,such as titanium, the stem insert 10 connection region 210 can be matedwith the head connector 110 which is disposed within the head component300. In various embodiments, the connection region 210 may be mated tothe head connector 110 via a taper adapter (not shown). The taperadapter may come in various lengths in order to allow for the correcthead height adjustment in order to ensure the implant fits the patient'sanatomy.

The stem insert 210 includes a stem neck portion 284 and a stemconnector 286. The stem neck portion 284 is designed to fit between theopening formed when the curved recessed regions 290 a and 290 b of thestem mold first component 202 and stem mold second component 204 arejoined. The stem connector 286 can be in the form of a Morse taperthrough which to connect to the head connector portion 110 of FIG. 9B.Returning to FIGS. 6 and 8, in various embodiments, the stem connectorportion 284 can also include surface roughening features or a surfacetexture to facilitate placement and fit of the stem connector portion284 with the head connector portion 110 of FIG. 9B. It is understoodthat the stem insert 210 can be made in differing lengths and widths toprovide further customization of the temporary implant depending on thepatient's needs.

With further reference to FIGS. 6 and 8, the stem insert 210 furtherdefines a securing screw 212 receiving opening 288. When the stem insert210 is disposed with in the assembled mold portions 202 and 204, thesecuring screw 212 can be advanced through the opening formed betweenelements 238 a and 238 b and down into the opening 288. The securingscrew 212 fixes and holds the stem insert 210 in a stationary positionwithin the cavity. In addition, the securing screw 212 also prevents thethreads of the inserter/extractor from flowing cement.

To connect the stem component mold 200 together, the rod 228 is passedthrough the alternating hook shaped openings 224 a and 224 b of theopposing stem component mold portions 202 and 204, respectively, asshown in FIG. 6. As explained above, the rod 228 may be insert moldedinto the mold portions 202. Similar to the description above, thearrangement provides a piano hinge for the stem mold component 200 bywhich to open or close the stem component mold 200.

The present teachings further provide methods of providing and using themodular cement mold. Although the methods are disclosed as used withcertain embodiments of the present teachings, it is understood that themethods disclosed can be used with any of the mold embodiments detailedabove herein.

First, a surgeon or assistant will mix the appropriate antibiotic loadedcement or add an antibiotic to the particular cement. It is understoodthat the preparation of the cement is performed according to the labelinstructions of the particular cement. For example, about two grams ofantibiotic are mixed with each 40 gram packet of bone cement powderwhich is then mixed with a corresponding number of 20 milliliterampoules of a liquid monomer. The bone cement can be apoly-methyl-methacrylate (PMMA) cement such as those produced under thetrade names Generation 4™, CMW1, CMW2, CMW3, Zimmer Dough Type, orZimmer LVC, or a MMA-styrene copolymer cement such as that producedunder the trade names Howmedica, Simplex P, or Zimmer Osteobond, or anMMA-methyl acrylate copolymer such as that produced under trade namesCobalt™ G-HV or Cobalt™ HV sold by Biomet. Once the appropriateantibiotic loaded bone cement is mixed, the bone cement is put within adelivery device, such as a cement gun. It is understood that an adaptormay be employed to accommodate different types of delivery devices orcement guns.

The appropriately sized mold portions 102 and 104 and mold portions 202and 204 along with the related appropriately sized components, such asthe head connector 110 or stem insert 210 are selected to form acustomized fit for both the articulating head 300 and femoral component400. It is understood that the head component 300 and the stem component400 can be varied in size to provide further customization of thetemporary implant depending on the patient's needs. The modular systemsof the present teachings can be provided as a plurality of differentlysized head components 100, stem molds 200, and related subcomponents.Once the appropriately sized components are selected, a surgeon willgenerally grasp the head component mold 100 and threadedly engage thenozzle of the delivery device into the access port 160. With the nozzlesubstantially sealing the access port 160, the surgeon will engage thedelivery device to dispense out the bone cement within the inner cavity106 a and 106 b formed within the head component mold 100. Afterremoving the cement delivery device, the surgeon then secures theself-cleaning cap 168 into the opening 160. Any excess cement willextrude out of the self-cleaning cap 168 and facilitate providing aflush implant.

The assembled mold 200 is connected as follows. It is understood that invarious embodiments, the mold 200 can be provided pre-assembled orpartially pre-assembled where some components must be connected by theuser prior to use. In the assembled device, the stem component moldfirst portion 202 and stem component mold second portion 204 areconnected using the connector 228 which is interlaced between the seriesof offset hooks 226 a and 226 b. The stem insert 210 is then aligned inthe cavity formed from elements 206 a and 206 b and secured via fixationmember 212. The recess or dispersion region 292 of the stem insert 210is arranged to be aligned with the opening 260 defined in the stemcomponent mold second portion 204 to provide proper flow of the materialaround the stem insert 210. The stem insert 210 is then fixed into themold portions 202 and 204 using the screw 212. The stem component moldfirst portion 202 and second portion 204 are then secured with thescrews 236 in each respective pair of bores 234 a and 234 b. Asmentioned above, and as shown in FIGS. 12A and 12B, the ledges 235 canbe heated or otherwise manipulated to provide the fold over region 237by which to rotatably trap the screw 236 therein. The fold over region237 can also be provided as pre-folded over the screw 236 and alleviatethe need for manipulation of the fold over region 237. The user thendelivers the bone cement within the inner cavity 206 a and 206 b to thethrough opening 260. The self-cleaning cap 168 is then fixed within theopening 260, and the excess bone cement will extrude through theopenings 174 defined in the self-cleaning cap 168.

Once the head component mold 100 and stem component mold 200 are filled,the assemblies can be placed on a nearby surface, such as a surgicaltable, to allow the cement to cure and cool while the surgeon moves onto another task, thereby substantially increasing the efficiency andreducing the time for the surgical procedure. Once the bone cement hassufficiently cured, the surgeon can grasp the head mold component 100and remove the screw 136 disposed in the opening formed by elements 134a and 134 b. The user attempts to back the screw 136 out of the threadedopening 134 b and towards the ledge 135. The screw 136 then engages theledge 135 and fold-over region 137 and is prevented from passing beyondthe fold-over region 137 and back through the opening 134 a. Theretention force of the ledge 135 and fold-over region 137 against therotating screw 136 pries the two mold component portions 102 and 104apart to free the implant. Similarly, the surgeon removes any otherscrews 236 from the openings formed by the pairs of bores 234 a and 234b using leverage from the ledges 235 and fold-over regions 237.

The stem component 400 of the temporary hip implant can then be simplyengaged in the intramedullary canal of the host femur. The air vent 402c formed in the stem component 400 facilitates the passage of air fromwithin the host femur to be expelled upon insertion of the stemcomponent 400.

The head component 300 is then disposed over the stem connector 286 viathe head connector 110, and the temporary implant is assembled. Thisimplanted head component 300 and stem component 400 allow the distendedjoint to be subsequently re-engaged with the temporary implant to enablelimited non-load bearing movement by the patient. The temporary implantallows the patient to generally sit up or be transported out of ahospital during the temporary recovery stage prior to having a revisiontype prosthesis subsequently implanted. During this time the antibioticin the bone cement leaches out to the infected area and soft-tissuetension is maintained.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the invention. Individual elements or features ofa particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the invention, and all such modificationsare intended to be included within the scope of the invention.

What is claimed is:
 1. A modular articulating cement spacer mold systemfor forming a temporary implant comprising: a mold first portionextending from a first end to a second end and having a first pluralityof open hooks formed on and extending away from a first exterior surfaceof the mold first portion; a mold second portion extending from a thirdend to a fourth end and having a second plurality of open hooks formedon and extending away from a second exterior surface of the mold secondportion; both the mold first portion and the mold second portion haverespective and corresponding interior surfaces defining a cavitytherebetween; a connection component pin extending between at least afirst hook of the first plurality of open hooks and at least a secondhook of the second plurality of open hooks; a self-cleaning capconfigured to be inserted into an opening formed by at least one of thefirst mold portion or the second mold portion, wherein the self-cleaningcap includes a threaded region, a closed bottom, an interrupted hollowregion, and a recessed containment region, wherein the opening furtherincludes a threaded opening, wherein the threaded region mates with thethreaded opening and as the self-cleaning cap is advanced through thethreaded opening any excess material passes around the closed bottom ofthe self-cleaning cap and through the interrupted hollow regions intothe recessed containment region of the self-cleaning cap; a plurality ofsurface features that include raised dimples and raised linear dashesextending from the interior surfaces; and a ventilation forming surfacefeature on the interior surface of at least one of the mold firstportion or the mold second portion; wherein the temporary implant is afemoral stem formable in the cavity.
 2. The modular articulating cementspacer mold system of claim 1, wherein the connection pin is a pluralityof connection pins coupling the first plurality of hooks to the secondplurality of hooks.
 3. The modular articulating cement spacer moldsystem of claim 1, wherein the ventilation feature comprises alongitudinal projection from at least one of the first inner surface orthe second inner surface to form a longitudinal depression along asubstantial length in the temporary implant that is the femoral stemformed by the femoral stem mold for ventilation during at least one ofimplantation or explanting the femoral stem.
 4. The modular articulatingcement spacer mold system of claim 1, further comprising: a reinforcinginsert for the temporary implant that extends from near the first end tonear the second end.
 5. The modular articulating cement spacer moldsystem of claim 4, further comprising: a stem component alignment screwthat is configured to interconnect the reinforcing insert and areceiving region portion formed by the mold first portion and the moldsecond portion when coupled together to hold the reinforcing insertwithin the cavity.
 6. The modular articulating cement spacer mold systemof claim 1, further comprising: wherein the ventilation forming surfacefeature on the interior surface of at least one of the mold firstportion or the mold second portion extends from a distal end to aproximal end of at least one of the respective interior surfaces.
 7. Themodular articulating cement spacer mold system of claim 1, furthercomprising: wherein at least one of the respective interior surfacesfurther comprises at least one other surface feature.
 8. A modulararticulating cement spacer mold system for forming a temporary implantcomprising: a mold first portion having a first interior surfaceextending along a longitudinal axis and shaped to form a first portionof a temporary elongated stem implant; a mold second portion having asecond interior surface extending along a longitudinal axis and shapedto form a second portion of the temporary elongated stem implant; and aventilation forming surface feature on at least one of the firstinterior surface of the mold first portion or the second interiorsurface of the mold second portion; a reinforcing insert for thetemporary implant removably placed within a cavity formed by the firstinterior surface and the second interior surface when the mold firstportion and the mold second portion are coupled together and removablewith a temporary implant formed within the mold first portion and themold second portion; a stem component alignment screw that is configuredto interconnect the reinforcing insert and a receiving region portionformed by the mold first portion and the mold second portion whencoupled together to hold the reinforcing insert within the femoral stemtemporary mold; wherein the ventilation forming surface feature includesat least one raised protrusion extending at least a portion of adistance of at least one of the first interior surface or the secondinterior surface; wherein the ventilation forming surface is configuredto form in the temporary implant a depression to allow trapped air toescape past the temporary implant upon insertion into a patient andprevent a vacuum upon explanting of the temporary implant.
 9. Themodular articulating cement spacer mold system of claim 8, wherein theventilation forming surface feature extends from a distal end of theinterior surface to a proximal end of the interior surface.
 10. Themodular articulating cement spacer mold system of claim 8, wherein theinterior surface of at least one of the mold first portion or the moldsecond component further comprises at least one other surface feature.11. The modular articulating cement spacer mold system of claim 10,wherein the at least one other surface feature decreases in density froma proximal end of the interior surface to a distal end of the interiorsurface.
 12. The modular articulating cement spacer mold system of claim10, wherein the interior surface of at least one of the mold firstportion or the mold second portion further comprises a plurality ofsurface features that include raised dimples and raised linear dashes.13. The modular articulating cement spacer mold system of claim 12,wherein the raised dimples are located towards the proximal end of themold and the raised linear dashes are located towards the distal end ofthe mold.
 14. The modular articulating cement spacer mold system ofclaim 12, wherein the raised linear dashes are disposed along the axisof removal of the temporary implant.
 15. The modular articulating cementspacer mold system of claim 8, wherein the cavity formed by the firstinterior surface of the mold first portion and the second interiorsurface of the mold second portion is shaped to mold a femoral stem. 16.The modular articulating cement spacer mold system of claim 15, whereinthe at least one raised protrusion of the ventilation forming surfacefeature comprises a raised longitudinal ledge to form a longitudinaldepression in a femoral stem formed by the femoral stem mold.
 17. Themodular articulating cement spacer mold system of claim 8, wherein themold first portion includes a first plurality of hooks coupled to asecond plurality of hooks of the mold second portion with one or moreconnection pins.
 18. The modular articulating cement spacer mold systemof claim 17, wherein the one or more connection pins can be molded toone of the mold first and second portions.
 19. The modular articulatingcement spacer mold system of claim 8, wherein the ventilation formingsurface feature is formed on an interior surface of each of the moldfirst portion and the mold second portion.
 20. A modular articulatingcement spacer mold system for forming a temporary implant comprising: amold first portion having a first interior surface extending along alongitudinal axis and shaped to form a first portion of a temporaryelongated stem implant; a mold second portion having a second interiorsurface extending along a longitudinal axis and shaped to form a secondportion of the temporary elongated stem implant; and a ventilationforming surface feature on at least one of the first interior surface ofthe mold first portion or the second interior surface of the mold secondportion and extending from a distal end of the interior surface to aproximal end of the interior surface; a reinforcing insert for thetemporary implant placed within a cavity formed by the first interiorsurface and the second interior surface when the mold first portion andthe mold second portion are coupled together; wherein the ventilationforming surface feature includes at least one raised protrusionextending at least a portion of a distance of at least one of the firstinterior surface or the second interior surface; wherein the ventilationforming surface is configured to form in the temporary implant adepression to allow trapped air to escape past the temporary implantupon insertion into a patient and prevent a vacuum upon explanting ofthe temporary implant; wherein the cavity formed by the first interiorsurface of the mold first portion and the second interior surface of themold second portion is shaped to mold a femoral stem.
 21. The modulararticulating cement spacer mold system of claim 20, wherein the interiorsurface of at least one of the mold first portion or the mold secondcomponent further comprises at least one other surface feature.
 22. Themodular articulating cement spacer mold system of claim 20, furthercomprising: one or more connection pins to couple the mold first portionand the mold second portion; wherein the mold first portion includes afirst plurality of hooks, the mold second portion includes a secondplurality of hooks, and the one or more connection pins couples thefirst plurality of hooks and the second plurality of hooks.
 23. Themodular articulating cement spacer mold system of claim 22, wherein theone or more connection pins can be molded to one of the mold first andsecond portions.
 24. The modular articulating cement spacer mold systemof claim 22, wherein at least one of the first plurality of hooks or thesecond plurality of hooks are open hooks.